How can I setup a looping animation in blender game engine?
you can use the action actuator set to ping pong. It plays the animation once through properly, and then plays it backwards. The tricky thing here is the correlation from frames to logic ticks. If you left the default settings, there will be 60 logic ticks per second, and 20 frames per second. 120 logic ticks is exactly 2 seconds worth, so we need 40 frames to be 2 seconds worth of frames. make an animation of your object that is 40 frames long.



On the action actuator, set the start frame to frame 0, and the end frame to frame 40. Now, your animation will play through from frame 0 to 40, then will play it backwards from frame 40 to frame 0, looping endlessly.